content: /**
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.observable.internal.operators;
  
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import io.reactivex.common.*;
  import io.reactivex.common.disposables.CompositeDisposable;
  import io.reactivex.common.exceptions.Exceptions;
  import io.reactivex.observable.*;
  import io.reactivex.observable.internal.disposables.EmptyDisposable;
  
  public final class CompletableAmb extends Completable {
      private final CompletableSource[] sources;
      private final Iterable<? extends CompletableSource> sourcesIterable;
  
      public CompletableAmb(CompletableSource[] sources, Iterable<? extends CompletableSource> sourcesIterable) {
          this.sources = sources;
          this.sourcesIterable = sourcesIterable;
      }
  
      @Override
      public void subscribeActual(final CompletableObserver s) {
          CompletableSource[] sources = this.sources;
          int count = 0;
          if (sources == null) {
              sources = new CompletableSource[8];
              try {
                  for (CompletableSource element : sourcesIterable) {
                      if (element == null) {
                          EmptyDisposable.error(new NullPointerException("One of the sources is null"), s);
                          return;
                      }
                      if (count == sources.length) {
                          CompletableSource[] b = new CompletableSource[count + (count >> 2)];
                          System.arraycopy(sources, 0, b, 0, count);
                          sources = b;
                      }
                      sources[count++] = element;
                  }
              } catch (Throwable e) {
                  Exceptions.throwIfFatal(e);
                  EmptyDisposable.error(e, s);
                  return;
              }
          } else {
              count = sources.length;
          }
  
          final CompositeDisposable set = new CompositeDisposable();
          s.onSubscribe(set);
  
          final AtomicBoolean once = new AtomicBoolean();
  
          CompletableObserver inner = new Amb(once, set, s);
  
          for (int i = 0; i < count; i++) {
              CompletableSource c = sources[i];
              if (set.isDisposed()) {
                  return;
              }
              if (c == null) {
                  NullPointerException npe = new NullPointerException("One of the sources is null");
                  if (once.compareAndSet(false, true)) {
                      set.dispose();
                      s.onError(npe);
                  } else {
                      RxJavaCommonPlugins.onError(npe);
                  }
                  return;
              }
  
              // no need to have separate observers because inner is stateless
              c.subscribe(inner);
          }
  
          if (count == 0) {
              s.onComplete();
          }
      }
  
      static final class Amb implements CompletableObserver {
          private final AtomicBoolean once;
          private final CompositeDisposable set;
          private final CompletableObserver s;
  
          Amb(AtomicBoolean once, CompositeDisposable set, CompletableObserver s) {
              this.once = once;
              this.set = set;
              this.s = s;
          }
  
          @Override
          public void onComplete() {
              if (once.compareAndSet(false, true)) {
                  set.dispose();
                  s.onComplete();
              }
          }
  
          @Override
          public void onError(Throwable e) {
              if (once.compareAndSet(false, true)) {
                  set.dispose();
                  s.onError(e);
              } else {
                  RxJavaCommonPlugins.onError(e);
              }
          }
  
          @Override
          public void onSubscribe(Disposable d) {
              set.add(d);
          }
  
      }
  }
  